What process involves the ingestion of particles by cells?

Phagocytosis is the process that specifically involves the ingestion of large particles or pathogens by cells. It is a type of endocytosis, where the cell membrane engulfs the particle, enclosing it within a vesicle called a phagosome. This process is crucial for the immune response, as it allows for the removal of debris and the destruction of microbes or foreign materials.

In contrast to phagocytosis, pinocytosis is a form of endocytosis that involves the uptake of fluids and small solutes, rather than larger particles. This is often termed "cellular drinking." Exocytosis, on the other hand, is the process by which cells expel materials, involving the fusion of vesicles with the cell membrane to release contents outside the cell. Endocytosis broadly encompasses both phagocytosis and pinocytosis as methods for cells to internalize substances. Therefore, while all these processes relate to the movement of substances across the cell membrane, phagocytosis specifically refers to the ingestion of larger particles.